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no.1 / March 2010 ISSN 1453 - 7303


4


No.1 / March 2010

4


No.1 / March 2010


No.1 / March 2010


ns =

n H net

Cu1 =

U

j

2 æ L öV Hnet = Hbrut - åhr = Hbrut - åç l +z ÷ è D ø 2g

V=

2g (Hbrut - Hnet ) pD2 ® Q= V = SV 4 æ L ö åçèl D +z÷ø

H net

= 3,65

gH net

U j (Rj )

=

Cm1 =

Pturb

p D jn 60

4Q / p 2 D - d butuc 2 cond

n H net

Q H net


Power coefficient Cp (V)

0.6 0.4 0.2 0

Cp (V) 0

0.5

1

Liquid current velocity V (m/s)

H (m) 2 4 6 8 10 12

V (m/s) 5,49 7,77 9,52 10,99 12,29 13,46

Q (m3/s) 1,55 2,20 2,69 3,11 3,47 3,80

P (kW) 16,7 47,3 86,9 133,8 186,9 245,7

n (r.p.m.) 577 817 1000 1155 1291 1414

ns 1591 1591 1591 1591 1591 1591


Fig.25


where

Dp1 = f (Dp2 )

58 18


is expressed by the difference in volumetric efficiency of motors, which possible in a range of identical motors due to manufacturing errors, as follows:

or

or


K=1.2


d 2


64 18


NATIONAL PROFESSIONAL ASSOCIATION OF HYDRAULICS AND PNEUMATICS IN ROMANIA


HIDRAULICA